Tunnel kiln



June 2,9 1926. 1,590,462

w. E. WILSON E-r AL.

TUNNEL KI LN Filed June 14, 1924 2 Sheets-Sheet l Www@ June 29 1926. 1,590,462

w. E. WILSON ET An.

TUNNEL KILN l Filed June 14, 1924 2 Sheets-Sheet 2 WWE mmf@ fQ/Uy G7 fyi/662@ @ym Waz,

Patented June 29, 1926.

UNITED STATES PATENT OFFICE.

WILLIAM E. WILSON, or MASON CITY, IOWA, AND HENRY of.` LYxxEN, OF MINNE- APoLIs, MINNESOTA. l

TUNNEL KILN'.

Application led June 14, 1924. Serial No. 720,115.

The present invention relates to kilns of the tunnel type through which wares may be moved or conveyed in stacks or decks, as upon cars..

Where, in kilns of this type, the sectional area of the cooling section is approximately thev same as that of the rest of the kiln, the cooling of the Ware is accomplished by radiation of the walls which in turn may be cooled by air circulating in the walls, if made hollow for that purpose, or outside the walls, or air cooled pipes may be used in the cooling section of the kiln to remove the heat Aradiated from the wares, or air may be circulated 'through the Wares in the cooling tunnel proper. These have the disadvantage of requiring long cooling sections, with the attendant cost of installation and maintenance, and the difficulty of controlling the air in the case of cooling with air circ-ulation in the tunnel sections, and not having the advantages that may be had yby convec tion of the cooling medium.

In kilhs having drying and heating sections where the heating gases are circulated through the ware in the passages of the sections the control of the circulation and the progression of the heating gases through the tunnel` have not, heretofore, been satisiactorily controlled and regulated so as to obtain a uniformy and efficient circulation and distribution of the heating medium as well as a uniform Withdrawal of the medium at the cnt-ry end of the kiln.

Among the objects of our invention are to provide the cooling section of the kiln with space additional to that simply required for the passage of the ware, preferably above the Ware passage and preferably at least equal ip height to or of greater height than the ware passage in added extension there- Y to, depending upon the height, the cooling medium, such as air, should rise above the ware, it being understood, however, that such space might be vertically beneath such passage, if'desired, as well as above such passage whereby the convection currents may rise or descend vertically in the space for the proper convection action and return into the ware at successive places or parts for progression through the ware to eHect the cooling action, to obtain proper convection action and for giving space or place to the relatively coolerv medium which may, in turn, progressively of the cooling section and permitting thek rising of such. medium through the Ware, as it is heated by the Ware and into the space provided vertically above or below the ware; to provide for an elevated exit of the heated medium inthe space above the' ware; to provide for :cooling the ware progressively whereby the cold medium is partially heated in the relatively cool part of the section and rises in temperature or takes up heat in stages,y the medium rising above the ware and being cooler and heavier than the medium further in the section, then passing downwardly through afurther or forward part of the Ware 'to displace the hotter medium rising to the space above, and so on to the end of the section when .the hot-test medium is exhausted at the upper part of such space, the hot'air being then used for heating or drying or both in the heating and Adrying sections of the kiln, if desired; to

provide for 'controlling of the coldmedium supplied or admitted to the section; to provide a sealing passage between the firing or burning section of the kiln and the cooling section thereof; to provide for preferably a single hot medium duct preferably extending the length of the drying and pre-heating sections of the kiln; to provide for lead bleeders to such duct from the cross ducts on the car decks; to provide for multiple controlled exhaust ports; to provide means such as anv exhaust fan' for exhausting" the gases or the other medium along the car decks and from the duct; to preferably provide the bleeders at intervals, as at every second car or the like; to provide means for controlling and regulating the section or withdrawal at each b eeder duct, such as by the use of dempers or valves and the like; to provide end 10 of the kiln.

for forcing the hot gases, near the roct'rof the kiln, to descend into the Ware by the drawing off of the cooled gases at the bot- `tom of the cars; to discharge hot medium ently possessed7 by the invention.

Referring to the drawings, showing a preferred embodiment of the invention, Fig.

1 is a longitudinal vertical sectional view' through a kiln constructed in accordance with the invention; Fig. 2 is a longitudinal y horizontal sectional view of the same; Fig. 3

is a vertical sectional view taken longitudinally through 'the hot medium duct and the adjacent parts of the kiln; Fig. 4f is a transverse sectional view taken on line 4 4 of Fig. 1 at the entry end of thc kiln; Fig. 5 is a transverse sectional view taken on line 5-5 of Fig. 1, and through the drying section of the kiln; Fig. 6 isa transverse sectional view taken on line 6-6`ot` Fig. 1 and through the pre-heating or heating section of the kiln; Fig. 7 is a transverse sectional view taken on line 7--7, and through the burning or tiring section of the kiln; Fig. 8 is a transverse sectional view taken on line 8 8, and through the sealing section of the kiln; and, Fig. 9 is a transverse sectional view taken on line 9'9, and through the cooling section of the kiln.

Referring now more particularly to the drawings, the kiln illustrating the invention comprises a drying section 1, a heating or pre-heating section 2, a firing or burning section 3, a sealing section 4, and a cooling section 5, all arranged in longitudinal order to provide therethrough a ware passage 6 through which a train oi cars 7, carrying the decks or stacks 8 of ware, may pass or travel from the entry end 9 to the discharge Suitable gates or doors 11 and 12 may be provided respectively at the entry and dischargingr ends 9 and 10 of the kiln.

The cooling section 5 of the kiln comprises a lower passage part 13 and an upper extension 14 for providing therein a chamber or space 15 such that the space 15 may be in additional height at least Yequal to and preferably greater than the height :of the passage 6 itself. Although, as shown in Fig. 1, this space is of substantially rectangular forni,

it is to be understood it might be inclined upwardly from the end 16 to the end 17 thereof without departing from the spirit of the invention. At the upper end portion 17 is provided a suitable outlet passage or duct 18 for the exhaust or withdrawal of the hot or heated medium in the chamber 15, this medium having been heated by the ware passing along the lower part of the cooling section in its cooling action. At ltheother end and in the lower part Iof the section 5, preferably at the sides of the passage 6 and opposite cross-ducts 19 provided in the car decks 8 are provided cold air ducts 20 and 21 through which the cold medium or cold air may be `admitted into the lower part of the passage 6 near thedischarge end thereof and of the section 5. There is shown a plurality of these ducts, three in number as shown in Fig. 2 ofthe drawings, but it is to be understood that any desired number may be used, but they will be grouped more or less proximately to the discharge end of the section 5. Each of these ducts are provided with valves 22 and 23 for regulating and controlling the admission of the cold medium into the passage 6 in the section 5.

In operation of this part of the kiln the cars 7 pass toward the discharge end of the section 5 and cold medium is admitted at the lower part of the passage 6 and into the cross-ducts 19. Inasmuch as the wares are placed in vertical position so that the air may pass vertically through the ware from the duct 19, it will be apparent that the cold air or cold medium will pass upwardly from the duct 19 through the ware and into the chamber 15. The rst ascent of such medium will not have a great rise and probably will be at the height shown by the dotted line portion 24 shown in F ig. 1 of the drawings. The rise of this medium, which has been heated by the ware, will displace the hotter medium in the chamber 15 and cause the same to descend into further ware and hence through the same into a cross-duct 19 and then laterally into the passage 6, where the medium will then proceed or progress in a direction opposite to the travel of the train and enter succeeding ducts 19 and pass upwardly through succeeding decks of wares and again rise into the chamber 15, this time at a greater height than previously and the process will continue in this manner with a greater rise of the medium at each successive descent and ascent of the medium until it arrives at the end 17 of the chamber and then being ot such a. temperature that it no longer has'any cooling characteristic and will then be withdrawn and exhausted through the duct 18 and used where desired, preferably in aiding in drying or heating the decks in the drying and heating sections of the kiln.

In this way it will be apparent that the cooling is made more or less unitormL and under control of the operator and in a coollill) ing section that is much shorter in length than have heretofore been required and at a greater rapidity than have heretofore been possible. The progress of the medium from one end to the other end of the cooling section is uniform and etiicient.y A I In order that this medium may not be wasted or lost by admission to other parts of the kiln, the latter is provided, at the rear of the cooling section, with a sealing passage 26 of such a size in cross-sectional area as that Vthe car and the deck will substantially fill this passage as the same pass through from the burning section to the' cooling section. Fig. 8 shows a cross section of this passage with a car and ware therein.

At the rear of the sealing section is provided a burning section, a detailed ldescription of which will not be required here inasmuch as this part of the kiln already forms part of another applicationand the operation and function of which will be readily understood by those skilled in the art.

At the rear of'the burning section is located the heating or pre-heating section and a duct 27 whichfleads from the rear end of the burning section and extends the full length of the heating and drying sectionto one side thereof and beneath the same as shown in Figs. 3, 4, 5 and 6 of the drawings.

` At intervals along the sides of the drying and heating sections are provided lateral ports 28 and 29 colnmunicating with the Ware passages in said sections and leading into passages 30, 31, 32 and ducts 27 as clearly shown in Fig. 6 of the drawings. Each of the ports 28 and 29 is provided with a control or regulatingr damper or valve 33 so that the exhaust or withdrawal of the gases from the passage may be controlled or regulated as desired. The ports 28 and 29 are preferably located opposite the crossducts 19 of the car decks also as clearly shown in Fig. 6 ot' the drawings.

Further to the rear of the section and above the same is provided or located a duct 34 having a blower or fan 35 having its eX- haust pipe communicating with a vertical duct 36 which communicates at its lower end with the horizontal duct 27 as clearly shown in Fig. 3 of the drawings. The vduct 34 communicates by a plurality of apertures or l ports 37, 38, 39, and 41 at intervals into.

the upper part of the passage .6 mto the heating and drying sections of the klln as clearly shown in Fig. 1. The tan 4may be operated by any suitable means, as by an electric motor or the like, and it will be aparent from the above description that some of the heated gases passing in the duct 27 may be drawn therefrom through the duct 36 and discharged into the duct 34 for admission into the assage 6 through the ports 37, 38, 39, 40 an 41.

inga discharge 44 for carryingotfthe exhausted media or the gases from the kiln, ,the t exhauster being suitably Aoperated by an eleci tric otor 45 mounted upon the 'entry end of the kiln.

It will be noted from the above description l that the meansffor conducting the ht gases through the drying and burning sections is controlled at multiple points or stations for controlling and regulating thev suction or Withdrawal of the gases from the passage of the sections and the cross-ducts of the decks and that these gases may pass upwardly into the duct 34 and be delivered into the upper part of the passage at the most efficient points so as to force these gases downwardly through the car decks and ware for avertical circulation therethrough and progressively toward the entry end of the kiln. l

While we have herein `described and upon the drawings shown a preferred form of the invention, it is to be understood that the invention is not limited to the particular details, constructions and arrangement of parts described andshown, but that it also comprehends other details, constructions and arrangements of parts without departing from the spirit thereof. l

Having thus described our invention, vwe claim:

1. A kiln comprising a cooling section having a ware passage and a convection space above the' passage.

2. A kiln comprisingV a cooling section having a ware passage and a chamber above said passage and of a height at, least equal .to the height Iof the passage whereinA the cooling medium ma act 1n accordance with the laws of convection currents.

3. A kiln comprising a cooling' section having a Ware passage extending upwardly a substantial distance to provide a chamber above said passage,`and means for admitting cooling medium in the lower part of the passa'ge.

4. A kiln comprising a cooling section having a ware passage extending upwardly a substantial distance to provide a chamber above-said passage, -means for admitting cooling medium in the 'lower art of the passage, and means for regulating the admission of said medium into said passage.

5. A kiln comprising a cooling section having a ware passage extending upwardly a substantial distance to provide' a chamber above said assage, and means at the-u per art of sai chamber for conveying o the ot medium from the chamber.

6. In a tunnel kiln having a burning section and e cooling section, the cooling secloll tion comprising a ware passageand an eX.- tension vertically of the passage and approximatel of equal area to the passage, for

8. A. kiln comprising a cooling section having a short ware passage and a chamber of substantially the same length of the passage above the passage.

9. A. kiln comprising a cooling section having a ware passage and a convection current chamber above the passage, means for admitting cold air at a lower part of the passage near one end thereof, and means for carrying o'iI the hot gases at the upper part of the chamber at the other end thereof.

10. A kiln comprising a cooling section having a ware passage and a convection current chamber above the passage, and an lair exit at the upper part of the chamber at an y end thereof.

11. A kiln comprising a cooling section and a burning section, a sealing section between said burning and cooling sections.

12. A. kiln comprising a cooling section and a burning section, a sealing section between said burning and cooling sections, and means above the cooling section for giving play for the currents of convection of the cooling section acting upon the ware in the cooling section, the sealing section substantially cutting off admission of the cooling medium into the burning section.

13. A kiln comprising a cooling section, means for vertically progressively cooling the ware passing through the section.

14. A method of cooling ware consisting in forcing cooling medium progressively in ascending and descending paths through the ware andinto a convection space for "free action of the convection currents in Vertical relation to the ware.'

15. A method of cooling ware consisting in forcing cooling medium progressively in ascending and descending paths through the ware and into a convection space for free action of the convection currents above the ware.

16. A method of cooling ware consisting in forcing cooling medium progressively in ascending and descending paths through the ware and into a convection space for. free action of the convection currents above ,the ware, regulating the rate of admission of the cooling medium to the ware.

17. s; method of cooling ware consisting in forcing cooling medium progressively in amending and descending paths through insonne the ware, increasing the succeeding rise and fall of the medium as the same progresses ilpng the ware in the cooling section oit the 18. A method of cooling ware consisting in forcing cooling medium progressively in ascending and descending paths through the ware, increasing the succeeding rise and fall of the medium as the same progresses along the Ware in the cooling section of the kiln, and regulating the rate of the rise and `tall of the medium.

19. A kiln comprising heating and burning sections, a gas duct leading from the burning section and extending along the heating section, and bleeders for admitting and drawing the gases to and from the wares at intervals along the heating section. 20. A kiln comprising heating and burning sections, a gas duct leading from the burning section and extending along the heating section, and means for admitting the gases to an upperpart of the heating section and for drawing the gases from the lower part of the section for causing a descent of the gases through the ware, said means acting to admit the gases to a further part of the heating section for progressive vertical circulation of the gases through the ware.

21. ln a kiln, comprising a heating. section, a single hot gas duct extending alongT the side and base of the section, multiple bleeders for controlling the withdrawal of the gases from the ware passage in the section, and means for conveying the withdrawn and hot gases `to the upper part of the passage at progressive intervals for a thorough circulation of the gases in the ware.

22. A kiln comprising drying, heating and burning sections, a passage extending through said sections, a duct extending laterally of the drying and heating sections and connected to the burning section, a plurality of exhaust ports between the passage and the duct at intervals therealong, and means for drawing heating medium from said passage through said ports and into said ducts and conveying the medium to the upper part of said drying and heating sections for descending circulation of the medium in the ware in the passage.

23. A kiln comprising drying, heating and burning sections, a passage extending through said sections, a duct extending laterally of the drying and heating sections and connected to the burning section, a plurality of exhaust ports between the passage and the duct at intervals therealong, multiple means for regulating and controlling the passage of heating medium through saidI ports.

24. A kiln comprising drying, heating and 'iti lli@

burning sections, a passage extending through said sections, a duct extending laterally of the drying and heating sections and connected to the burning section, a plurality of exhaust ports between the passage and the duct at 'intervals therealong, and means for drawing heating medium from said passage through said ports and into said ducts and conveying the mediumA to the upper part of sai-d ydrying and heating sections for descending circulation of the medium in the ware in the passage, multiple means for regulating and controlling the passage of heating medium through said ports.

25. A kiln comprising a cooling section and a burning section, a sealing section of reduced cross-sectional area and substantially the same in cross-sectional area of the material passing through the kiln., betweensaid burning and cooling sections.

In witness whereof, we hereunto subscribe our names to this specification.

VILLIAM E. WILSON. HENRY G. LYKKEN. 

